I can never see Springsteen or U2 too many times. I think I have seen Springsteen over 100 times (have tickets for 2 more shows next month) and U2 probably about 20 times.
I regret not seeing Nirvana when I had a chance.
I think I have seen Springsteen over 100 times (have tickets for 2 more shows next month
I have yet to see Eric Clapton, that is a top priority though.